The long-term goal of the proposed research is to understand how modification of proteins by myristylation affects protein structure and function. This will be accomplished by studying N-myristyl transferase (NMT), the enzyme which catalyzes attachment of myristate to proteins, as well as its protein substrates. NMT will be purified from mammalian liver, and used as an antigen for production of polyclonal and monoclonal antisera. Anti-NMT antibodies will be employed, in conjunction with NMT activity assays, to probe the subcellular localization of NMT in normal and Rous sarcoma virus-transformed cells. In addition, the gene encoding NMT will be cloned and used to express NMT. Cellular substrates for NMT will be identified by immunoreaction with anti-myristylglycine antibodies, and effects of oncogenic transformation on the expression and distribution of myristylated proteins will be studied. Additional experiments will focus on the myristylated transforming protein of Rous sarcoma virus, pp60(v-src), which requires myristylation in order to bind to membranes and elicit transformation. The effect of altering fatty acid hydrophobicity, chain length, and protein sequence context of the myristate moiety on pp60(v-src) will be tested in an in vitro membrane binding assay. Since myristate is attached to numerous viral structural proteins and oncogenes, as well as to proteins involved in growth control and signal transduction, the proposed studies should aid in understanding the basic biochemical mechanisms which regulate cell growth.